Recent Work on Oenothera. 
209 
NOTES ON RECENT LITERATURE. 
Recent Work on CEnothera. 
rpHE remarkable genetical phenomena exhibited by the species of 
CEnothera are stimulating a rapid production of papers on 
various aspects of the subject, which is fast passing beyond the 
reach of any but specialists. 
Professor H. de Vries' has published a preliminary account of 
experiments in hybridising CE. biennis and CE. rnuricata r' The off¬ 
spring of the first cross between these species differs according to 
the way in which the cross is made : in both cases the hybrid 
markedly inclines in appearance towards the pollen parent. The 
hybrid from each cross, when self-fertilised, breeds absolutely 
true for an indefinite number of generations. 
The two hybrids may be designated as (M 5 B $ ) and ( B 5 M $ ) 
respectively. They may be crossed together in two reciprocal 
ways, and from such crosses de Vries obtained the following 
remarkable results. The cross (M ? B <y) $ x $ gave 
offspring which corresponded absolutely with rnuricata, shewing 
no trace of the characters of biennis , The reciprocal cross 
(B 2 M 3 ), ? x (M 2 B £) $ gave pure biennis free from all 
signs of rnuricata. 
It will be seen that in both cases the characters which appear 
in the offspring are those handed on by the same sex as that by 
which they were introduced in the original muricata-biennis cross. 
For example, in the cross (M 2 B <y) ? x (B 5 M $) the mother 
received the rnuricata characters from her mother, and the father 
received the rnuricata characters from his father: the offspring is 
rnuricata. The same applies, mutatis mutandis, to the reciprocal 
cross producing biennis. “ The characters of the grandfather 
cannot be transmitted to the grandchildren by the mother ; nor 
can those of the grandmother be transmitted to the grandchildren 
by the father.” (p. 99). 
The conclusion is that the pollen grains and ovules of a plant 
carry different sets of characters, so that B ? x M$ is really a 
different cross from M ? xBg. The conception of the different 
hereditary content of pollen and ovules is familiar through the work 
of Miss Saunders and Mr. Bateson on Matthiola- and earlier studies 
of de Vries on CEenothera nanella 3 : but the present instance is novel 
in several respects, the most curious being that tins “heterogamy” 
(as de Vries rather unfortunately calls it) here occurs in pure species. 
It is shown that the characters transmitted by the pollen of biennis 
are closely similar to those typical of the external form of the 
species; those borne by the ovules are of a quite different type, 
* When referring subsequently to species of CEnothera the generic 
initial will be omitted. 
1 “ Uber doppeltreziproke Bastarde von CE. biennis und CE. rnuricata .” 
Biol. Centralbl, XXXI., p. 97, Feb., 1911. 
2 Report IV. to the Evol. Comm, of the Royal Soc., pp. 5, 36; 
1908. 
3 “fiber die Zwillings-bastarde von CE. nanella." Ber. d. d. bot. 
Ges., XXVIa., p. 667; 1908. 
